Is it better to rely on an intention file or a database for a web chatbot?
Recognising intents is only a small step in developing a chatbot. It's fine to use an ML classifier with training data for that, no need to keep the original list of intents.

However, you should really think about the next step: how are you getting your bot to conduct a dialogue, rather than firing off single responses to user queries. That is where things get difficult, and that is also what distinguishes a good chatbot from a simple-minded Eliza-clone.

The programming language/framework you use is not relevant.